With the development of computer hardware, hardware capable of carrying out a parallel operation using one or more cores has appeared on the stage. Unlike the existing method contriving to increase an operation speed with the increase in clock of a CPU, the parallel operation environment makes operations parallel using a plurality of processors or vector operation to increase the operation speed, which is suitable for high speed operation of multiple physical objects.
As hardware providing the parallel operation environment has been developed, physical engines of computer programs operating using the hardware have been developed accordingly. The physical engines such as Havok or Physx currently used in the parallel operation environment are generally used for accelerating a simulation or collision process of rigid bodies or particles. However, these engines have excellent performance to trace the motion of the rigid bodies, but have common performance to simulate the motion and texture of cloth so as to express clothes.
The cloth simulation method according to the prior art expresses the motion and texture of the whole cloth by setting multiple vertices on the cloth to be traced and calculating the variation over time in position of the respective vertices. In order to calculate the variation in position of the respective vertices, the prior art technology implements Verlet integration to the positions of the respective vertices over time and converges the integrated value so as to satisfy the limitation that a length of cloth is maintained constant, thereby calculating the position of the vertices.
However, the prior art technology using Verlet integration has problems in that it can be optimally implemented only under the environment that there are a number of processors, that a converging speed of the integrated value for the positions of the respective vertices is slow, and that converging of the integrated value is not guaranteed, degrading the stability. In addition, as the number of the vertices increases, operation load increases excessively, and limitation condition that a length of cloth is essentially maintained constant is used so that physical properties of cloth is not expressed freely.
In a real-time 3D application including all games such as a sports game, a war game, a multi-media online role-playing game (MMORPG), etc., in which characters similar to humans enter the stage, clothes are an important factor. However, as set forth above, the prior technology is not suitable to express the motion and texture of cloth. Thus, it is true at present that in order for expressing the cloth in the costumes, previously operated and stored data is read out and implemented with an animation process, or otherwise, clothes animation is not used at all.
Further, recently in Europe (E-tailor project, Fraun Hopper, Miralab), Japan (Digital Fashion Ltd.), and Republic of Korea (I-fashion), a 3D virtual system has been developed with which a user can virtually wear clothes. While a real-time cloth simulation technology for expressing clothes chosen by a user in real time is the core point in such a system, there is no system adopting such a real time cloth simulation technology at present. Therefore, there is a need to develop a real time cloth simulation technology capable of not only carrying out a real time process, but also having high quality.